Filter for a funnel for a coffee making apparatus

ABSTRACT

With respect to a filter with a fastening device for a coffee-making apparatus of the type where water is brought to a boil in a closed container, whereupon the water is pressed through a riser pipe into a funnel, where boiling water extracts aromas and flavour from the ground coffee, whereupon the finished coffee beverage is filtered back into the closed container through a filter placed at the outlet of the funnel, where the filter is fastened by means of a fastening device which reaches through the riser pipe, the objective is to provide a filter where the aroma and flavour of the ground coffee is exploited as well as possible and where the filter offers a comparatively large filter surface for the finished coffee, and where the filter can easily be removed from the funnel and cleaned with a view to further coffee-making. Moreover, the filter must be easily replaceable by dismantling the handle and locking clip and fitting these on a new filter.  
     According to the principles of the present invention, this objective is met by a filter ( 1 ) equipped with a centrally fitted handle ( 10 ), which extends into the funnel ( 2 ); where the filter ( 1 ) is held in the riser pipe ( 5 ) by means of a centrally fitted locking clip ( 4 ) with locking devices ( 6 ) which fit corresponding locking devices ( 7 ) inside the riser pipe ( 5 ) at an appropriate distance from the filter ( 1 ), and where the handle ( 10 ) and locking clip ( 4 ) are joined by means of appropriate devices ( 8 ) which extend through the filter ( 1 ).

SCOPE OF THE INVENTION

[0001] This invention relates to a filter with a fastening device for acoffee-making apparatus of the type where water is brought to a boil ina closed container, whereupon the water is pressed through a riser pipeinto a funnel, where boiling water extracts aromas and flavour from theground coffee, whereupon the finished coffee beverage is filtered backinto the closed container through a filter placed at the outlet of thefunnel.

[0002] 1. State of Art

[0003] Such a filter has been known since 1958, where it was made as anaccessory to the coffee-making apparatus mentioned above. Parts of thisknown design is described in DK 90776 and DK 98310.

[0004] The filter composition known from this design comprised a plasticplate, the underside of which was equipped with radial projectinggrooves, which is comprised the filter surface as well as allowed thesteam to pass up through the funnel when the water was boiling. By meansof the filter surface thus provided, the coffee ground should remain inthe funnel; this was only feasible where the coffee had been coarselyground. Finally, the filter plate was attached by means of a spiralspring running through the riser pipe; this spiral spring had a hookwhich hooked onto the lower edge of the riser pipe.

[0005] However, this design involves a series of drawbacks, insofar atthe filter plate will frequently become stuck due to dried-out coffeeground; thus making it impossible to release the filter plate, eventhough the spiral spring has been released from the lower edge of theriser pipe.

[0006] 2. The Objective of the Invention

[0007] Consequently, the basis for this invention is the object ofproviding a filter for a coffee-making apparatus of the type mentionedin the introduction, where the aroma and flavour of the ground coffee isexploited as well as possible by means of a filter which offers acomparatively large filter surface for the finished coffee, and wherethe filter can be easily removed from the funnel and cleaned with a viewto further coffee-making. Moreover, the filter must be easilyreplaceable by dismantling the handle and locking clip and fitting theseon a new filter.

[0008] According to the principles of the present invention, thisobjective is met by a filter of the type initially mentioned, where thefilter is equipped with a centrally fitted handle, which extends into afunnel; where the filter is held in the riser pipe by means of acentrally fitted locking clip with locking devices which fitcorresponding locking devices inside the riser pipe at an appropriatedistance from the filter; and where the handle and locking clip arejoined by means of appropriate devices which extend through the filter.

[0009] With a filter according to the principles of the presentinvention, the aromas and flavour of the ground coffee can be exploitedas well as possible, insofar as the filter offers a large filter surfacefor the finished coffee in comparison to previous filter types. Thismeans that finely ground coffee can also be used, thus ensuring betterutilisation of the aroma and flavour of the coffee. The filter can alsobe easily removed from the funnel and cleaned with a view to furthercoffee-making as the handle extends into the funnel, thus making it easyto get a hold of and release from the grip of the locking clip on thelocking devices of the riser pipe. Moreover, the filter is easilyreplaced, as the handle and locking clip can be disassembled andrefitted on a new filter.

[0010] In an appropriate embodiment, the present invention consists in amanner essentially known of a vitrified surface of glass or a type ofplastic with a specific opening. This facilitates a filter surfacewhich, by means of the best filtering possible, ensures a reliable flowduring filtering, just as the specific opening features very fewdeviations from the projected opening. This means that even very finelyground coffee can be filtered with a large degree of certainty that nosediments will appear in the finished coffee beverage. However, thevitrified glass surface is mechanically fragile, and with a view toproviding a more durable filter it is proposed that the filter should ina manner essentially known consist of a filter ring made from plastic,with a hub and a number of spokes extending between the hub and thering; a filter medium is stretched between these parts.

[0011] This embodiment of the filter provides a filter which similarlyoffers optimum filtering, but where the filter is also made from a typeof plastic with a lower mass density and a greater ultimate strength inmechanical terms than that of glass. If this type of plastic is furtherdefined as polypropylene (PP), the use of the filter in households givesno cause for concern.

[0012] In one embodiment of the invention, the filter medium may consistof a mesh which is stretched over a filter ring with spokes and a hub,ensuring that the mesh is affixed in relation to the funnel. In oneembodiment of the invention, the mesh consists of polypropylene (PP)which facilitates optimum joining of the materials by means of welding,thus facilitating reliable fastening of the mesh.

[0013] Instead of polypropylene, the mesh may also consist of polyesteror polyamide. In connection with the use of other types of plastic, itmust, however, be observed that the material must be able to withstandtemperatures >100° Celsius without deformation.

[0014] Disposable paper filters may also be used as filter mediuminstead of a mesh.

[0015] In one appropriate embodiment of the filter according to theprinciples of the present invention, the filter circumference on theside facing the funnel is fitted with radial slits. These slits are usedfor various purposes. During boiling, they serve to distribute therising steam equally throughout the outer diameter of the entire filter,thus occasioning an optimum mixture of coffee and water while ensuringhomogenous temperatures in the funnel.

[0016] With a view to ensuring increased stability of the fitted filter,it is proposed that the central area of the filter should be displacedaxially towards the outlet of the funnel towards the riser pipe, andthat the filter should have centrally positioned devices to achievecorrect fitting of handle and locking clip. Increased stability isachieved by making the filter more rigid with respect to mechanicalstresses, such as removal and placing of the filter, and by correctlyfitting the handle and locking clip, the filter will always be correctlypositioned in relation to the radial slits and the mechanical stresseson the filter.

[0017] One embodiment in accordance with the principles of the presentinvention proposes that the locking devices of the locking clip consistof a number of pins, each having a locking hook to catch a correspondinglocking protuberance in the riser pipe. Moreover, in an appropriateembodiment it is proposed that the locking hooks (6) and lockingprotuberances (7) catch each other by means of sloping surfaces. Thus,the filter can be released from the funnel by means of a single radialmovement of the handle inside the funnel, thus releasing the lockinghooks from their clasp on the locking protuberances in the riser pipe.An alternative embodiment might propose that the locking hooks andlocking protuberances be designed as a bayonet joint, but in that casethe handle would need to turned, rather than being moved radially.Regardless of the embodiment, it will be advantageous to have thelocking clip consist of a type of plastic, which in one advantageousembodiment may be polyoxymethylene (POM).

[0018] With a view to correct mounting of handles and locking clip, aparticularly advantageous embodiment proposes to have the devices forjoining the handle and locking clip consist of a thread and a threadedpin, respectively. It is also proposed that the filter should, in acentral position on the side facing the locking clip, have a recesswhich corresponds to the outline of the locking clip and which serves tocentre the locking clip, and that the filter should otherwise beequipped with protrusions ensuring that the filter cannot be placed in awrong position between the handle and locking clip.

[0019] Further advantageous embodiments of the invention will appearfrom the dependent claims.

SHORT DESCRIPTION OF THE DRAWINGS

[0020] The drawing depicts an example of an embodiment of the presentinvention. In this drawing:

[0021]FIG. 1 depicts an axial cross-section through a filter inaccordance with the principles of the present invention mounted over theoutlet of the funnel, and

[0022]FIG. 2 depicts a filter in accordance with the principles of thepresent invention seen from the side facing the funnel.

[0023] In FIG. 1, the filter 1 is shown when mounted in the funnel 2 ofa coffee-making apparatus which shall not be specified in more detail.The circumference 3 of the filter 1 rests on the bottom of the funnel 2and, by means of the locking clip 4, reaches down into the riser pipe 5,where the locking hooks 6 hook onto the locking protuberances 7 in theriser pipe 5. In the embodiment shown here, a threaded pin 8 stretchesaxially from the locking clip 4 up through the central part 9 of thefilter 1 to the axial thread 11 of the handle 10, where the handle 10and locking clip 4 can be joined by screwing them together.

[0024] On the side facing the opening of the funnel of the central part9 of the filter 1, it is possible to make out a protuberance 12, whichfits a corresponding recess (not shown) in the underside of the handle10.

[0025] On the side of the central part 9 of the filter 1 which faces theriser pipe 5, it is possible to make out a recess 13 which fits acorresponding protuberance 14 on the locking clip 4.

[0026] It may be advantageous in terms of safety to have the lockinghooks 6 and locking protuberances 7 hook onto each other by means ofsloping surfaces, as this would make it possible for the filter torelease itself in the event of an uncontrollable rise in theoverpressure of the closed container, thus avoiding an explosion.

[0027]FIG. 2 depicts the side of the filter 1 facing the riser pipe 5.In this embodiment of the present invention, this side of the filter 1consists of a mesh stretched over a filter ring 3 (made from plastic)with a hub 17 and a number of spokes 16 stretching between hub and ring.This ensures that the mesh is fixed in relation to the funnel. In oneembodiment of the invention, the mesh consists of polypropylene (PP)which facilitates optimum joining of the materials by means of welding,thus facilitating reliable fastening of the mesh. The radial slits 15can be seen on the filter circumference 3; these slits 15 serve variouspurposes. During boiling, the slits 15 serve to distribute the risingsteam equally throughout the outer diameter of the entire filter, thusoccasioning an optimum mixture of coffee and water while ensuringhomogenous temperatures in the funnel. During filtering, the slits 15assist in the filtering of the finished coffee on equal footing with theother filter material.

[0028] The embodiment shown is an example only and is not limited tothat which is depicted in the drawings. Changes and variations which areobvious to experts are also included in the scope of this invention.

1. A filter with a fastening device for a coffee-making apparatus of thetype where water is brought to a boil in a closed container, whereuponthe water is pressed through a riser pipe into a funnel, where boilingwater extracts aromas and flavour from the ground coffee, whereupon thefinished coffee beverage is filtered back into the closed containerthrough a filter placed at the outlet of the funnel, where the filter isfastened by means of a fastening device which reaches through the riserpiper, characterised in that the filter (1) is equipped with a centrallyfitted handle (2), which extends up into the funnel (2); that the filter(1) is held in the riser pipe (5) by means of a centrally fitted lockingclip (4) with locking devices (6) which fit corresponding lockingdevices (7) inside the riser pipe (5) at an appropriate distance fromthe filter (1), and that the handle (10) and locking clip (4) are joinedby means of appropriate devices (8,11) which extend through the filter(1).
 2. Filter according to claim 1 , characterised in that the filter(1) in a manner essentially known consists of vitrified glass or asimilar material with a specific opening.
 3. Filter according to claim 1, characterised in that the filter (1) in a manner essentially knownconsists of a filter ring (3) made from plastic, with a hub (17) and anumber of spokes (16) extending between the hub (17) and the ring (3); afilter medium (18) is stretched between these parts (3, 16, 17). 4.Filter according to claim 3 , characterised in that the type of plasticused is polypropylene (PP).
 5. Filter according to any of the previousclaims, characterised in that the filter circumference (3) on the sidefacing the funnel (2) is fitted with radial slits (15).
 6. Filteraccording to any of the previous claims, characterised in that thefilter (1) has centrally positioned devices (12,13) to ensure thathandle (10) and locking clip (4) are correctly mounted.
 7. Filteraccording to any of the previous claims, characterised in that thecentral part (9) of the filter (1) is displaced axially towards theoutlet of the funnel (2) to the riser pipe (5).
 8. Filter according toany of the previous claims, characterised in that the locking devices onthe locking clip (4) comprises a number of pins, each of which featuresa locking hook (6) which hooks onto a corresponding locking protuberance(7) in the riser pipe (5).
 9. Filter according to claim 8 ,characterised in that the locking hooks (6) and locking protuberances(7) catch each other by means of sloping surfaces.
 10. Filter accordingto claim 8 , characterised in that the locking hooks (6) and lockingprotuberances (7) are designed as a bayonet joint.
 11. Filter accordingto any of the previous claims, characterised in that the locking clip ismade from a type of plastic.
 12. Filter according to claim 10 ,characterised in that the type of plastic used is polyoxymethylene(POM).
 13. Filter according to any of the previous claims, characterisedin that the devices used to join the handle (10) and locking clip (4)consists a thread and a thread pin.